windows: Fix autohide taskbar dosen't automatically appear when Zed is maximized (#16806)

Closes #12313

This PR introduces the following improvements:
1. Fixed the issue where the auto-hide taskbar wouldn't automatically
appear when Zed is maximized.
2. Refactored the `WM_NCCALCSIZE` code, making it more human-readable.

Release Notes:

- Fixed auto-hide taskbar would refuse to show itself when `Zed` is
maximized on
Winodws([#12313](https://github.com/zed-industries/zed/issues/12313)).

---------

Co-authored-by: Mikayla Maki <mikayla@zed.dev>

crates/gpui/src/platform/windows/system_settings.rs

@@ -1,16 +1,24 @@
 use std::ffi::{c_uint, c_void};
 
-use util::ResultExt;
-use windows::Win32::UI::WindowsAndMessaging::{
-    SystemParametersInfoW, SPI_GETWHEELSCROLLCHARS, SPI_GETWHEELSCROLLLINES,
-    SYSTEM_PARAMETERS_INFO_UPDATE_FLAGS,
+use ::util::ResultExt;
+use windows::Win32::UI::{
+    Shell::{SHAppBarMessage, ABM_GETSTATE, ABM_GETTASKBARPOS, ABS_AUTOHIDE, APPBARDATA},
+    WindowsAndMessaging::{
+        SystemParametersInfoW, SPI_GETWHEELSCROLLCHARS, SPI_GETWHEELSCROLLLINES,
+        SYSTEM_PARAMETERS_INFO_UPDATE_FLAGS,
+    },
 };
 
+use crate::*;
+
+use super::WindowsDisplay;
+
 /// Windows settings pulled from SystemParametersInfo
 /// https://learn.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-systemparametersinfow
 #[derive(Default, Debug, Clone, Copy)]
 pub(crate) struct WindowsSystemSettings {
     pub(crate) mouse_wheel_settings: MouseWheelSettings,
+    pub(crate) auto_hide_taskbar_position: Option<AutoHideTaskbarPosition>,
 }
 
 #[derive(Default, Debug, Clone, Copy)]
@@ -22,19 +30,20 @@ pub(crate) struct MouseWheelSettings {
 }
 
 impl WindowsSystemSettings {
-    pub(crate) fn new() -> Self {
+    pub(crate) fn new(display: WindowsDisplay) -> Self {
         let mut settings = Self::default();
-        settings.init();
+        settings.update(display);
         settings
     }
 
-    fn init(&mut self) {
+    pub(crate) fn update(&mut self, display: WindowsDisplay) {
         self.mouse_wheel_settings.update();
+        self.auto_hide_taskbar_position = AutoHideTaskbarPosition::new(display).log_err().flatten();
     }
 }
 
 impl MouseWheelSettings {
-    pub(crate) fn update(&mut self) {
+    fn update(&mut self) {
         self.update_wheel_scroll_chars();
         self.update_wheel_scroll_lines();
     }
@@ -71,3 +80,100 @@ impl MouseWheelSettings {
         }
     }
 }
+
+#[derive(Debug, Clone, Copy, Default)]
+pub(crate) enum AutoHideTaskbarPosition {
+    Left,
+    Right,
+    Top,
+    #[default]
+    Bottom,
+}
+
+impl AutoHideTaskbarPosition {
+    fn new(display: WindowsDisplay) -> anyhow::Result<Option<Self>> {
+        if !check_auto_hide_taskbar_enable() {
+            // If auto hide taskbar is not enable, we do nothing in this case.
+            return Ok(None);
+        }
+        let mut info = APPBARDATA {
+            cbSize: std::mem::size_of::<APPBARDATA>() as u32,
+            ..Default::default()
+        };
+        let ret = unsafe { SHAppBarMessage(ABM_GETTASKBARPOS, &mut info) };
+        if ret == 0 {
+            anyhow::bail!(
+                "Unable to retrieve taskbar position: {}",
+                std::io::Error::last_os_error()
+            );
+        }
+        let taskbar_bounds: Bounds<DevicePixels> = Bounds::new(
+            point(info.rc.left.into(), info.rc.top.into()),
+            size(
+                (info.rc.right - info.rc.left).into(),
+                (info.rc.bottom - info.rc.top).into(),
+            ),
+        );
+        let display_bounds = display.physical_bounds();
+        if display_bounds.intersect(&taskbar_bounds) != taskbar_bounds {
+            // This case indicates that taskbar is not on the current monitor.
+            return Ok(None);
+        }
+        if taskbar_bounds.bottom() == display_bounds.bottom()
+            && taskbar_bounds.right() == display_bounds.right()
+        {
+            if taskbar_bounds.size.height < display_bounds.size.height
+                && taskbar_bounds.size.width == display_bounds.size.width
+            {
+                return Ok(Some(Self::Bottom));
+            }
+            if taskbar_bounds.size.width < display_bounds.size.width
+                && taskbar_bounds.size.height == display_bounds.size.height
+            {
+                return Ok(Some(Self::Right));
+            }
+            log::error!(
+                "Unrecognized taskbar bounds {:?} give display bounds {:?}",
+                taskbar_bounds,
+                display_bounds
+            );
+            return Ok(None);
+        }
+        if taskbar_bounds.top() == display_bounds.top()
+            && taskbar_bounds.left() == display_bounds.left()
+        {
+            if taskbar_bounds.size.height < display_bounds.size.height
+                && taskbar_bounds.size.width == display_bounds.size.width
+            {
+                return Ok(Some(Self::Top));
+            }
+            if taskbar_bounds.size.width < display_bounds.size.width
+                && taskbar_bounds.size.height == display_bounds.size.height
+            {
+                return Ok(Some(Self::Left));
+            }
+            log::error!(
+                "Unrecognized taskbar bounds {:?} give display bounds {:?}",
+                taskbar_bounds,
+                display_bounds
+            );
+            return Ok(None);
+        }
+        log::error!(
+            "Unrecognized taskbar bounds {:?} give display bounds {:?}",
+            taskbar_bounds,
+            display_bounds
+        );
+        Ok(None)
+    }
+}
+
+/// Check if auto hide taskbar is enable or not.
+fn check_auto_hide_taskbar_enable() -> bool {
+    let mut info = APPBARDATA {
+        cbSize: std::mem::size_of::<APPBARDATA>() as u32,
+        ..Default::default()
+    };
+    let ret = unsafe { SHAppBarMessage(ABM_GETSTATE, &mut info) } as u32;
+    ret == ABS_AUTOHIDE
+}